This invention relates to a propylene-based resin composition and to a molding method using the same, more particularly to a propylene-based resin composition high in rigidity and resistance to impact, excellent in resistance to scratching, and also excellent in moldability (injection moldability or press injection moldability), and to a molding method using the same.
Recently, propylene-based composite materials comprising a propylene-based resin material incorporated with an inorganic filler (e.g., talc) and/or elastomer have been widely used for automobile parts, e.g., bumpers, instrument panels, door trims and pillar trims, because of their well-balanced properties and excellent moldability.
The propylene-based resin material is frequently incorporated with an elastomer, when it is to be used for automobile parts required to have high impact-related characteristics. However, increasing the elastomer content tends to cause loss of bending modulus of elasticity and bending strength. A filler, e.g., talc, has been incorporated in an attempt to improve these properties, but has failed to significantly improve bending strength, although successfully improving bending modulus of elasticity. Therefore, the conventional propylene-based composite material, although exhibiting a high bending modulus of elasticity, is not well-balanced with respect to impact resistance and bending strength.
Many automobile interiors are those which a person directly comes into contact with, and their feel of material, i.e., feel of rigidity, firmness or the like, depends on their bending strength. Therefore, a propylene-based composite material is required to be well-balanced with respect to impact resistance and bending strength.
For improvement of resistance of propylene-based resin composition to scratching, various techniques have been proposed; e.g., incorporation of a specific polyethylene (Japanese Patent Laid-Open No.73034/1982), use of a filler of specific particle size (Japanese Patent Laid-Open No.8235/1982), and addition of a nucleating agent or the like to improve crystallinity and hence surface hardness.
These techniques achieve the above objects to some extent. However, the propylene-based resin composition is required to have still higher resistance to scratching, as embossed patterns on the molded articles are becoming more diversified.
It is an object of the present invention to provide a propylene-based resin composition which gives the molded articles excellent in resistance to scratching, and, at the same time, in moldability (injection moldability or press injection moldability) and balanced properties (high rigidity and impact strength), to solve the above problems. It is another object of the present invention to provide a method for molding the above propylene-based resin composition, to produce high-performance industrial parts and automobile parts, in particular automobile interiors, at low cost.
The inventors of the present invention have found, after having extensively studied to solve the above problems, that the resin composition solving the above problems can be obtained by incorporating a specific propylene-based resin composition of high impact resistance with a specific high-crystallinity propylene resin material and inorganic filler or, depending on circumstances, pigment-containing resin material; or, depending on circumstances, by incorporating the above specific propylene-based resin composition of high impact resistance and/or high-crystallinity propylene resin material and specific inorganic filler with a specific ethylene/xcex1-olefin copolymer rubber and/or specific polyethylene and/or fatty acid amide or its derivative, and by mixing or melting/kneading these components, reaching the present invention.
The first invention provides a propylene-based resin composition produced by mixing and/or melting/kneading the following components (A) and (B):
(A) Propylene-based resin composed of the following components (a1), (a2) and (a3); 90 to 40 wt. %
(a1) Propylene/ethylene block copolymer, composed of 60 to 83 wt. % of crystalline propylene homopolymer component (a1-1 unit) and 17 to 40 wt. % of ethylene/propylene random copolymer component (a1-2 unit) containing 30 to 52 wt. % of ethylene and having a weight-average molecular weight of 230,000 to 600,000; and having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 15 to 150 g/10 min. and number of gels of 100 or less for those having a size of 50 xcexcm or more in the molded article of 25 cm2 (area) and 0.5 mm (thickness); 100 wt. parts.
(a2) Talc having an average particle size of 0.5 to 15 xcexcm; 0 to 200 wt. parts.
(a3) Ethylene/xcex1-olefin copolymer rubber, containing 20 to 50 wt. % of xcex1-olefin of 3 to 8 carbon atoms and having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 100 g/10 min; 0 to 20 wt. parts.
(B) Propylene-based resin material composed of the following components (b1) and (b2); 10 to 60 wt. %:
(b1) Propylene homopolymer or propylene/ethylene block copolymer, having a component insoluble in orthodichlorobenzene at below 120xc2x0 C. accounting for 8 wt. % or more of the component insoluble at below 100xc2x0 C., when fractionated with orthodichlorobenzene as the solvent, wherein the component insoluble at below 100xc2x0 C. has a weight-average molecular weight of 200,000 or more and melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 70 g/10 min; 15 to 80 wt. parts.
(b2) Talc or wollastonite having an average particle size of 0.5 to 15 xcexcm; 20 to 85 wt. parts.
The second invention provides a propylene-based resin composition produced by mixing and/or melting/kneading the following components (A) and (B):
(A) Propylene-based resin material composed of the following components (a1), (a2) and (a3): 90 to 40 wt. %
(a1) Propylene/ethylene block copolymer, composed of 60 to 83 wt. % of crystalline propylene homopolymer component (a1-1 unit) and 17 to 40 wt. % of ethylene/propylene random copolymer component (a1-2 unit) containing 30 to 52 wt. % of ethylene and having a weight-average molecular weight of 230,000 to 600,000; and having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 20 to 150 g/10 min. and number of gels of 100 or less for those having a size of 50 xcexcm or more in the molded article of 25 cm2 (area) and 0.5 mm (thickness); 100 wt. parts.
(a2) Talc having an average particle size of 0.5 to 15 xcexcm; 0 to 200 wt. parts.
(a3) Ethylene/xcex1-olefin copolymer rubber containing 20 to 50 wt. % of xcex1-olefin of 3 to 8 carbon atoms and having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 15 g/10 min; 0 to 10 wt. parts.
(B) Propylene-based resin material composed of the following components (b1) and (b2); 10 to 60 wt. %:
(b1) Homopolypropylene or propylene/ethylene block copolymer, having a component insoluble in orthodichlorobenzene at below 120xc2x0 C. accounting for 10 wt. % or more of the component insoluble at below 100xc2x0 C., when fractionated with orthodichlorobenzene as the solvent, wherein the component insoluble at below 100xc2x0 C. has a weight-average molecular weight of 200,000 or more and melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 20 g/10 min; 100 wt. parts.
(b2) Talc having an average particle size of 0.5 to 15 xcexcm; 0 to 200 wt. parts.
The third invention provides a propylene-based resin composition, composed of 100 wt. parts of the totaled components (A) and (B) for the first invention incorporated with 10 wt. parts or less of the following component (C), and produced by mixing and/or melting/kneading these components:
(C) Propylene-based colorant material, composed of the following components (c1), (c3), (c4), (c5) and (c6):
(c1) Propylene homopolymer, propylene/ethylene block copolymer, propylene/ethylene random copolymer, polyethylene or ethylene-based rubber, having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 200 g/10 min.; 20 to 99.9 wt. %.
(c3) Ethylene/xcex1-olefin copolymer rubber containing 20 to 50 wt. % of xcex1-olefin of 3 to 8 carbon atoms and having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 100 g/10 min; 0 to 90 wt. %.
(c4) Polyethylene having a density of 0.920 g/cm3 or more and melt flow rate (190xc2x0 C., load: 2.16 kg) of 1 to 100 g/10 min; 0 to 90 wt. %.
(c5) Fatty acid amide or its derivative; 0 to 30 wt. %.
(c6) Pigment; 0.1 to 80 wt. %.
The fourth invention provides a propylene-based resin composition, composed of 100 wt. parts of the component (a1) for the component (A) for the first or third invention incorporated with 20 wt. parts or less of the following component (a4):
(a4) Polyethylene having a density of 0.920 g/cm3 or more and melt flow rate (190xc2x0 C., load: 2.16 kg) of 1 to 100 g/10 min.
The fifth invention provides a propylene-based resin composition, composed of 100 wt. parts of the totaled components (b1) and (b2) for the component (B) for the first, third or fourth invention incorporated with 30 wt. parts or less of the following component (b3):
(b3) Ethylene/xcex1-olefin copolymer rubber containing 20 to 50 wt. % of xcex1-olefin of 3 to 8 carbon atoms and having a melt flow rate (230xc2x0 C., load: 2.16 kg) of 0.3 to 100 g/10 min.
The sixth invention provides a propylene-based resin composition, composed of 100 wt. parts of the totaled components (b1) and (b2) for the component (B) for the first, or one of third to fifth invention incorporated with 30 wt. parts or less of the following component (b4):
(b4) Polyethylene having a density of 0.920 g/cm3 or more and melt flow rate (190xc2x0 C., load: 2.16 kg) of 1 to 100 g/10 min.
The seventh invention provides a propylene-based resin composition, composed of 100 wt. parts of the totaled components (b1) and (b2) for the component (B) for the first, or one of third to sixth invention incorporated with 0.1 to 9 wt. parts of a fatty acid amide or its derivative.
The eighth invention provides a propylene-based resin composition, composed of 100 wt. parts of the totaled components (b1) and (b2) for the component (B) for the first, or one of third to seventh invention incorporated with 0.1 to 5 wt. parts of a higher fatty acid or its metallic salt.
The ninth invention provides a method for molding the propylene-based resin composition of one of the first to eight inventions by injection molding or press injection molding.
The tenth invention provides an automobile part produced by the method of the ninth invention.
The present invention is described in more detail.
The propylene-based resin composition of the present invention is composed of the following components (A) and (B), and produced by mixing and/or kneading/granulation.
(1) Component (A)
The component (A) for the present invention is the propylene-based resin material composed of the following components (a1), (a2) and (a3):
(i) Component (a1)
The component (a1) is the major component for the propylene-based resin material as the component (A). It is a propylene/ethylene block copolymer, composed of crystalline propylene homopolymer component (a1-1 unit) and ethylene/propylene random copolymer component (a1-2 unit).
The a1-2 unit contains ethylene at 30 to 52 wt. %, preferably 32 to 50 wt. %, more preferably 35 to 45 wt. %. The ethylene content beyond the above range may deteriorate impact strength of the propylene-based resin composition.
The a1-2 unit has a weight-average molecular weight of 230,000 to 600,000, preferably 250,000 to 500,000, more preferably 300,000 to 400,000. The molecular weight below the above range is undesirable, because it may deteriorate impact strength of the propylene-based resin composition, and that beyond the above range is also undesirable, because it may deteriorate outer appearances of the molded article. Contents of the a1-1 and a1-2 units of the propylene/ethylene block copolymer are 60 to 83 wt. %, preferably 65 to 80 wt. %, more preferably 70 to 77 wt. % for the former, and 17 to 40 wt. %, preferably 20 to 35 wt. %, more preferably 23 to 30 wt. % for the latter. An a1-1 unit content exceeding the above range coupled with an a1-2 unit content below the above range is undesirable, because it may deteriorate bending strength of the propylene-based resin material. On the other hand, an a1-1 unit content below the above range coupled with an a1-2 unit content exceeding the above range is also undesirable, because it may deteriorate impact strength.
The propylene/ethylene block copolymer as the component (a1) has a melt flow rate (230xc2x0 C., load: 2.16 kg, hereinafter referred to as MFR) of 15 to 150, preferably 20 to 150, more preferably 20 to 110, still more preferably 20 to 70 g/10 min. MFR beyond the above range is undesirable, because it may deteriorate outer appearances of the molded article when it is below the above range and deteriorate impact strength of the propylene-based resin composition when it exceeds the above range.
The propylene/ethylene block copolymer as the component (a1) has a number of gels of 100 or less, preferably 60 or less, more preferably 40 or less, for those having a size of 50 xcexcm or less in the molded article of 25 cm2 (area) and 0.5 mm (thickness). The number exceeding 100 is undesirable, because it may deteriorate outer appearances of the molded article and impact strength of the propylene-based resin composition.
The propylene/ethylene block copolymer having the above-described specific properties may be produced by polymerization (slurry, vapor-phase or block polymerization) in the presence of a catalyst of high stereoregularity, e.g., Ziegler or metallocene type catalyst. The polymerization may be effected either batchwise or continuous process. For production of the propylene/ethylene block copolymer, it is preferable, viewed from improved quality, to produce the crystalline propylene homopolymer component (a1-1 unit) first by homopolymerization of propylene, and then the ethylene/propylene random copolymer component (a1-2 unit) by random copolymerization of ethylene and propylene.
More concretely, the homopolymerization is effected in the presence of a catalyst, comprising a solid component prepared by bringing titanium tetrachloride and a halide of organic acid into contact with magnesium chloride, and combined with an organic aluminum or silicon compound, and then followed by the random copolymerization of ethylene and propylene.
The propylene/ethylene block copolymer may be incorporated further with another unsaturated compound, e.g., xcex1-olefin such as 1-butene, or vinyl ester such as vinyl acetate, to form the copolymer of 3 or more components or the mixture thereof, so long as the effect of the present invention is not notably damaged. It may be in the mold of pellet or powder.
(ii) Component (a2)
The component (a2) for the present invention is talc. Talc for the present invention preferably has an average particle size of 0.5 to 15 xcexcm, more preferably 2 to 10 xcexcm.
The talc having an average particle size in the above range can decrease expansion coefficient of the propylene-based resin composition, and brings other advantages, e.g., reduced shrinkage and outer appearances of good, controlled gloss. The average particle size can be determined by a laser-aided diffraction/scattering particle size distribution analyzer (e.g., HORIBA""s LA-920).
The talc can be obtained by finely crushing naturally occurring one by a mechanical means, and classifying the particles precisely. The crushed particles may be classified first roughly and then more precisely. The mechanical means include crushers, e.g., jaw, hammer, roll and jet crushers, and mills, e.g., screen, colloid, roll and vibration mills. The crushed talc particles are classified by the wet or dry method once or repeatedly to have a desirable average size for the present invention. The useful devices for classifying them include cyclone, cyclone air separator, micro separator, and sharp-cut separator. It is preferable to crush the talc to have a size in a specific range, and classify the crushed particles by a sharp-cut separator, to prepare the talc for the present invention.
The talc particles for the present invention may be as-received or surface-treated beforehand physically or chemically with an agent selected from various ones, e.g., silane coupling agent, higher fatty acid, metallic salt of fatty acid, unsaturated organic acid, organotitanate, resin acid and polyethylene glycol. Use of the surface-treated talc gives the propylene-based resin composition of further improved properties, e.g., moldability and impact strength.
(iii) Component (a3)
The present invention may be further incorporated with, in addition to the components (a1) and (a2), an ethylene/xcex1-olefin copolymer rubber as the component (a3) which contains an xcex1-olefin of 3 to 8 carbon atoms. Such xcex1-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-penetene-1.
The xcex1-olefin content is 20 to 50 wt. % on the whole ethylene/xcex1-olefin copolymer rubber, preferably 20 to 45 wt. %, more preferably 20 to 40 wt. %. The xcex1-olefin content beyond the above range is undesirable, because it may deteriorate impact strength when it is below the above range and deteriorate rigidity when it exceeds the above range.
The ethylene/xcex1-olefin copolymer rubber as the component (a3) has an MFR (230xc2x0 C., load: 2.16 kg) of 0.3 to 100, preferably 0.7 to 70, more preferably 1 to 30 g/10 min. The MFR beyond the above range is undesirable, because it may deteriorate moldability when it is below the above range and cause insufficient impact strength and surface hardness when it exceeds the above range.
(iv) Contents of the Components (a1) to (a3)
Content of the component (a2) in the component (A) is 0 to 200 wt. parts per 100 wt. parts of the component (a1), preferably 0 to 100 wt. parts, more preferably 0 to 60 wt. parts, still more preferably 0 to 40 wt. parts. The component (a2) is not an essential but an optional component, and may not be incorporated in the component (A). Nevertheless, however, incorporation of the component (a2) can decrease expansion coefficient of the propylene-based resin composition, and brings other advantages, e.g., reduced shrinkage and outer appearances of good, controlled gloss. However, the content exceeding 200 wt. parts per 100 wt. parts of the component (a1) is undesirable, because it may cause insufficient dispersion of the talc.
Content of the component (a3) in the component (A) is 0 to 20 wt. parts per 100 wt. parts of the component (a1), preferably 0 to 10 wt. parts, more preferably 2 to 9 wt. parts, still more preferably 2 to 6 wt. parts. The component (a3) is not an essential but an optional component, and may not be incorporated in the component (A). Nevertheless, however, incorporation of the component (a3) can bring an advantage of improved impact strength. However, the content exceeding 20 wt. parts per 100 wt. parts of the component (a1) is undesirable, because it may cause insufficient bending strength.
(v) Production of the Component (A)
The component (A) is obtained by mixing the above components (a1) to (a3) with each other. The mixing method is not limited, and the components (a1) to (a3) in a specific ratio are mixed by a known machine, e.g., Henschel mixer, tumbler and ribbon blender.
It is preferable that the mixing for production of the component (A) is followed by melting and kneading, and, depending on circumstances, further by granulation to mold the component into pellets. The kneading and granulation can be effected by the conventional kneader, e.g., extruder (e.g., of monoaxial or biaxial type), Banbury mixer, roll, Brabender Plastograph, or another kneader, set at 100 to 240xc2x0 C. Of these, an extruder, in particular biaxial extruder, is more preferable. In the above process, the components may be mixed and kneaded altogether or separately, e.g., part of the component (a1) is kneaded with the component (a3) or (a2), and the remainder is then kneaded with the mixture, to be granulated.
(2) Component (B)
The component (B) for the present invention is the propylene-based resin material composed of the following components (b1) and (b2):
(i) Component (b1)
The component (b1) for the present invention is a propylene homopolymer or propylene/ethylene block copolymer, having a component insoluble in orthodichlorobenzene at below 120xc2x0 C. accounting for 8 wt. % or more of the component insoluble at below 100xc2x0 C., when fractionated with orthodichlorobenzene as the solvent. More concretely, when the component (b1) is dissolved in orthodichlorobenzene as the solvent, its component insoluble in the solvent heated at 100xc2x0 C. is referred to as the one xe2x80x9cinsoluble at 100xc2x0 C.xe2x80x9d, and the component insoluble in the solvent heated at 120xc2x0 C. is referred to as the one xe2x80x9cinsoluble at 120xc2x0 Cxe2x80x9d. The component insoluble at 120xc2x0 C. accounts for 8 wt. % or more of the whole component insoluble at 100xc2x0 C., preferably 10 wt. % or more, more preferably 12 wt. % or more, still more preferably 15 wt. % or more. The component insoluble at 120xc2x0 C. accounting for less than 8 wt % is undesirable, because it may cause insufficient bending strength and bending modulus of elasticity.
For the component (b1) for the present invention, the component insoluble at 100xc2x0 C. has a weight-average molecular weight (Mw) of 200,000 or more, preferably 250,000 or more. The molecular weight below the above range is undesirable, because it may deteriorate impact strength of the component (b1).
The component (b1) for the present invention has an MFR of 0.3 to 70, preferably 0.5 to 50, more preferably 1 to 40 g/10 min. MFR beyond the above range is undesirable, because it may deteriorate outer appearances of the molded article when it is below the above range and cause insufficient impact strength of the propylene-based resin composition when it exceeds the above range.
The component (b1) may be a propylene homopolymer or propylene/ethylene block copolymer. When it is a propylene/ethylene block copolymer, it contains ethylene preferably at 1 to 15 wt. %, more preferably 1 to 10 wt. %, still more preferably 2 to 8 wt. % or so.
The propylene homopolymer or propylene/ethylene block copolymer having the above-described specific properties may be produced in the same manner as that for the above-described component (a1-1) or (a1).
(ii) Component (b2)
The component (B) for the present invention contains, in addition to the above-described component (b1), talc or wollastonite as the component (b2), having an average particle size of 0.5 to 15 xcexcm, more preferably 2 to 10 xcexcm.
The talc or wollastonite having an average particle size in the above range can decrease expansion coefficient of the propylene-based resin composition, and brings other advantages, e.g., reduced shrinkage and outer appearances of good, controlled gloss. The average particle size of talc or wollastonite can be determined by a laser-aided diffraction/scattering particle size distribution analyzer (e.g., HORIBA""s LA-920).
The talc can be obtained by finely crushing naturally occurring one by a mechanical means, and classifying the particles precisely. The crushed particles may be classified first roughly and then more precisely. The mechanical means include crushers, e.g., jaw, hammer, roll and jet crushers, and mills, e.g., screen, colloid, roll and vibration mills. The crushed talc particles are classified by the wet or dry method once or repeatedly to have a desirable average size for the present invention. The useful devices for classifying them include cyclone, cyclone air separator, micro separator, and sharp-cut separator. It is preferable to crush the talc to have a size in a specific range, and classify the crushed particles by a sharp-cut separator, to prepare the talc for the present invention.
The talc particles for the present invention may be as-received or surface-treated beforehand physically or chemically with an agent selected from various ones, e.g., silane coupling agent, higher fatty acid, metallic salt of fatty acid, unsaturated organic acid, organotitanate, resin acid and polyethylene glycol. Use of the surface-treated talc gives the propylene-based resin composition of further improved properties, e.g., moldability and impact strength.
Wollastonite is represented by the chemical formula CaSiO3 or CaO.SiO2, and normally in the form of needles or indefinite particles.
The wollastonite for the present invention preferably has an aspect ratio of 2 or more.
(iii) Contents of the Components (b1) and (b2)
Content of the component (b2) is 20 to 85 wt. parts per 100 wt. parts of the totaled components (b1) and (b2), preferably 25 to 80 wt. parts. Content of the component (b2) beyond the above range is undesirable, because it may not sufficiently reduce expansion coefficient and cause outer appearances of insufficiently controlled gloss when it is below 20 wt. parts, and cause insufficient dispersion of the talc or wollastonite when it exceeds 85 wt. parts.
(iv) Production of the Component (B)
The component (B) is obtained by mixing the components (b1) and (b2) with each other. These components may be molten and kneaded, after being mixed with each other, and, depending on circumstances, further granulated into pellets. The mixing, melting/kneading and granulation methods may be the same as those for producing the component (A).
(3) Contents of the Components (A) and (B)
Contents of the components (A) and (B) for the propylene-based resin composition of the present invention are 90 to 40 wt. %, preferably 85 to 45 wt. %, more preferably 80 to 55 wt. % for the component (A), and 10 to 60 wt. %, preferably 15 to 55 wt. %, more preferably 20 to 45 wt. % for the component (B). A component (A) content below the above range coupled with a component (B) content exceeding the above range is undesirable, because it may deteriorate impact strength of the propylene-based resin composition. On the other hand, a component (A) content exceeding the above range coupled with a component (B) content below the above range is also undesirable, because it may deteriorate rigidity.
The above composition of the high-fluidity propylene-based resin (Component (A)) and resin composition (Component (B)), the former containing the rubber component at a high content and the latter containing the high-crystallinity propylene-based resin and inorganic filler, gives the molded resin articles of sufficiently high rigidity and improved bending strength for the present invention.
(4) Additional Components (Optional)
The propylene-based resin composition of the present invention may be incorporated with, in addition to the above components (A) and (B), one or more of additional components (optional components), so long as the effect of the present invention is not notably damaged.
These additional components (optional components) useful for the present invention include antioxidant, e.g., phenol-, phosphorus- and sulfur-based ones; weathering-inhibiting agent, e.g., hindered amine-, benzophenone- and benzotriazole-based ones; nucleating agent, e.g., organoaluminum and organophosphorus compounds; colorant, e.g., quinacridon, perylene, phthalocyanine, titanium oxide, carbon black, azo-based pigment, iron red and ultramarine blue; whiskers, e.g., those of fibrous potassium titanate, fibrous magnesium oxysulfate, fibrous aluminum borate and calcium carbonate; filler component, e.g., carbon fibers and glass fibers; high-molecular-weight component, e.g., high-density and low-density polyethylene; and other additives, e.g., ultraviolet absorber, antistatic agent, dispersant, neutralizer, foaming agent, copper inhibitor, lubricant and flame-retardant.
These additional components may be incorporated in at least one of the constituent components (a1) to (a3) or (b1) and (b2) for the respective components (A) or (B) before hand, or while these constituent components are mixed with each other and, as required, molten and kneaded to prepare the component (A) or (B), or while the components (A) and (B) are mixed and molten/kneaded to prepare the propylene-based resin composition.
The propylene-based resin composition [II] of the present invention differs from the above-described propylene-based resin composition [I] in the following points, and the different points are described.
1. The propylene/ethylene block copolymer as the component (a1) has an MFR (230xc2x0 C., load: 2.16 kg) of 20 to 150, preferably 20 to 110, more preferably 20 to 70 g/10 min. MFR beyond the above range is undesirable, because it may deteriorate outer appearances of the molded article when it is below the above range and deteriorate impact strength of the propylene-based resin composition when it exceeds the above range.
2. The ethylene/xcex1-olefin copolymer rubber as the component (a3) has an MFR (230xc2x0 C., load: 2.16 kg) of 0.3 to 15, preferably 0.7 to 13, more preferably 1 to 10 g/10 min. The MFR beyond the above range is undesirable, because it may deteriorate moldability when it is below the above range and cause insufficient impact strength and surface hardness when it exceeds the above range.
3. Content of the Component (a3)
Content of the component (a3) in the component (A) is 0 to 10 wt. parts per 100 wt. parts of the component (a1). The component (a3) is not an essential component, and may not be incorporated in the component (A). Nevertheless, however, incorporation of the component (a3) brings an advantage of improving impact strength. However, the content exceeding 10 wt. parts per 100 wt. parts of the component (a1) is undesirable, because it may cause insufficient bending strength. The preferable content pd the component (a3) is 2 to 6 wt. parts.
4. The component (b1) is a propylene homopolymer or propylene/ethylene block copolymer, having a component insoluble in orthodichlorobenzene at below 120xc2x0 C. accounting for 10 wt. % or more of the component insoluble at below 100xc2x0 C., when fractionated with orthodichlorobenzene as the solvent. More concretely, when the component (b1) is dissolved in orthodichlorobenzene as the solvent, its component insoluble in the solvent heated at 100xc2x0 C. is referred to as the one xe2x80x9cinsoluble at 100xc2x0 C.xe2x80x9d, and the component insoluble in the solvent heated at 120xc2x0 C. is referred to as the one xe2x80x9cinsoluble at 120xc2x0 C.xe2x80x9d The component insoluble at 120xc2x0 C. accounts for 10 wt. % or more of the whole component insoluble at 100xc2x0 C., preferably 13 wt. % or more, more preferably 15 wt. % or more. The component insoluble at 120xc2x0 C. accounting for less than 10 wt. % is undesirable, because it may cause insufficient bending strength and bending modulus of elasticity.
5. The component (b1) for the present invention has an MFR of 0.3 to 20, preferably 0.5 to 15, more preferably 0.7 to 10 g/10 min. MFR beyond the above range is undesirable, because it may deteriorate outer appearances of the molded article when it is below the above range and cause insufficient impact strength of the propylene-based resin composition when it exceeds the above range.
6. The component (b2): Talc having an average particle size of preferably 0.5 to 15 xcexcm, more preferably 2 to 10 xcexcm, may be incorporated in addition to the component (b1). The talc having an average particle size in the above range can decrease expansion coefficient of the propylene-based resin composition, and brings other advantages, e.g., reduced shrinkage and outer appearances of good, controlled gloss.
7. Contents of the Components (b1) and (b2)
Content of the component (b2) is 0 to 200 wt. parts per 100 wt. parts of the component (b1), preferably 0 to 100, more preferably 0 to 60 wt. parts, still more preferably 2 to 60 wt. parts. The component (b2) is not an essential but optional component, and may not be incorporated. However, it is preferable to incorporate it, more preferably at 20 wt. parts or more. Incorporation of the component (b2) can decrease expansion coefficient of the propylene-based resin composition, and brings other advantages, e.g., reduced shrinkage and outer appearances of good, controlled gloss. However, the content exceeding 200 wt. parts per 100 wt. parts of the component (b1) is undesirable, because it may cause insufficient dispersion of the talc.
As described above, the propylene-based resin composition [II] of the present invention gives the molded resin articles of excellent properties, e.g., sufficiently high rigidity and bending strength, by combining the high-fluidity propylene-based resin (Component (A)) with the high-molecular-weight, high-crystallinity propylene-based resin (Component (B)).
The propylene-based resin composition [III] of the present invention is composed of 100 wt. parts of the totaled components (A) and (B) for the propylene-based resin composition [I] incorporated with 10 wt. parts or less, preferably 1 to 6 wt. parts, of the following Component (C), and produced by mixing and/or melting/kneading these components:
(1) Component (C)
The component (C) for the present invention is a colorant material composed of the following components (c1), (c3), (c4), (c5) and (c6):
(i) Component (c1)
The component (c1) has an MFR (230xc2x0 C., load: 2.16 kg) of 0.3 to 200, preferably 0.5 to 100 g/10 min., and is selected from the group consisting of propylene homopolymer, propylene/ethylene block copolymer, propylene/ethylene random copolymer, polyethylene and ethylene-based rubber. The coloration may be insufficient at an MFR less than 0.3 g/10 min., and defective outer appearances, e.g., uneven coloration, may result at an MFR more than 200 g/10 min.
The component (c1) may be a propylene homopolymer, propylene/ethylene block copolymer, propylene/ethylene random copolymer, polyethylene or ethylene-based rubber, so long as it is a polyolefin-based resin or rubber capable of dispersing the components (c5) and (c6). The resin or rubber having these specific properties may be produced by the methods for producing the components (A) and (B), and other known methods.
(ii) Component (c3)
The component (c3) is the same as the component (a3) for the above-described component (A).
(iii) Component (c4)
The component (c4) for the present invention is a polyethylene having a density of 0.920 g/cm3 or more, preferably 0.930 g/cm3 or more, and MFR (190xc2x0 C., load: 2.16 kg) of 1 to 100, preferably 1 to 50 g/10 min. Rigidity will be insufficient at the density below 0.920 g/cm3. Moldability will be insufficient at the MFR below the above range, and so will be impact strength at the MFR exceeding the above range.
The polyethylene useful for the component (b4) includes low-density, straight-chain low-density, medium-density and high-density polyethylene, of which high-density polyethylene is more preferable.
(iv) Component (c5)
The component (c5) for the present invention is a fatty acid amide or its derivative.
The concrete examples of these compounds include lauric, stearic, oleic, behenic, erucic, hydroxystearic, N-stearylerucic, ethylene-bis-stearic, ethylene-bis-oleic, and hexamethylene-bis-stearic acid amide.
(v) Component (c6)
The component (c6) for the present invention is a pigment component. The pigments useful for the component (c6) include the inorganic ones, e.g., carbon black, titanium oxide, iron red and ultramarine blue; and organic ones, e.g., quinacridon, perylene, phthalocyanine, azo-based pigment, and anthraquinone-based pigment.
(vi) Contents of the Components (c1), (c3), (c4), (c5) and (c6)
Content of the component (c1) in the component (C) is 20 to 99.9 wt. %, based on the (c1)+(c3)+(c4)+(c5)+(c6), preferably 30 to 95 wt. %. Uneven coloration may result at a component (c1) content of less than 20 wt. %, and insufficient coloration may result at more than 99.9 wt. %.
Content of the component (c3) in the component (C) is 0 to 90 wt. %, based on the (c1)+(c3)+(c4)+(c5)+(c6), preferably 0 to 80 wt. %. Insufficient rigidity may result at a component (c3) content of more than 90 wt. %.
Content of the component (c4) in the component (C) is 0 to 90 wt. %, based on the (c1)+(c3)+(c4)+(c5)+(c6), preferably 0 to 80 wt. %. Insufficient rigidity may result at a component (c4) content of more than 90 wt. %.
Content of the component (c5) in the component (C) is 0 to 30 wt. %, based on the (c1)+(c3)+(c4)+(c5)+(c6), preferably 0 to 20 wt. %. Insufficient rigidity may result at a component (c5) content of more than 30 wt. %, and such a content is undesirable.
Content of the component (c6) in the component (C) is 0.1 to 80 wt. %, based on the (c1)+(c3)+(c4)+(c5)+(c6), preferably 5 to 70 wt. %. Insufficient coloration may result at a component (c6) content of less than 0.1 wt. %, and insufficient dispersion of the pigment may result at more than 80 wt. %. Hence, the content beyond the above range is undesirable.
(vii) Production of the Component (C)
The component (C) is obtained by mixing the components (c1), (c3), (c4), (c5) and (c6) in the above ratio. These components may be molten and kneaded, after being mixed with each other, and, depending on circumstances, further granulated into pellets. The mixing, melting/kneading and granulation methods may be the same as those for producing the component (A).
(2) Composition of the Component (C)
Content of the component (C) in the propylene-based resin composition [III] of the present invention is 0 to 10 wt. parts per 100 wt. parts of the totaled components (A) and (B), preferably 0 to 6 wt. parts. The content exceeding 10 wt. parts may deteriorate rigidity of the composition and is also uneconomical.
The propylene-based resin composition [III] of the present invention is well-balanced with respect to rigidity and impact-resistant characteristics, and also high in resistance to scratching by including the high-fluidity propylene-based resin (Component (A)) and resin composition (Component (B)), the former containing the rubber component at a high content and the latter containing the high-crystallinity propylene-based resin and inorganic filler. It can also exhibit, when incorporated with another type of additive, pigment or the like, the resistance to scratching and low gloss required for automobile internals, e.g., instrument panels.
(3) Additional Components (Optional)
The propylene-based resin composition [III] of the present invention may be incorporated with, in addition to the above components (A), (B) and (C), one or more of additional components (optional components), so long as the effect of the present invention is not notably damaged.
These additional components (optional components) useful for the present invention include antioxidant, e.g., phenol- and phosphorus-based ones; weathering-inhibiting agent, e.g., hindered amine-, benzophenone- and benzotriazole-based ones; nucleating agent, e.g., organoaluminum and organophosphorus compounds; whiskers, e.g., those of fibrous potassium titanate, fibrous magnesium oxysulfate, fibrous aluminum borate and calcium carbonate; filler component, e.g., carbon fibers and glass fibers; high-molecular-weight component, e.g., high-density and low-density polyethylene; and other additives, e.g., ultraviolet absorber, antistatic agent, dispersant, lubricant, neutralizer, foaming agent, copper inhibitor, and flame-retardant.
These additional components may be incorporated in at least one of the constituent components for the components (A), (B) and (C) before hand, or while these constituent components are mixed with each other and, as required, molten and kneaded to prepare the component (A), (B) or (C), or while the components (A), (B) and (C) are mixed and molten/kneaded to prepare the propylene-based resin composition.
The propylene-based resin composition [IV] of the present invention comprises the component (A) for the propylene-based resin composition [I] or [III] which is further incorporated with the following component (a4) at 20 wt. parts or less per 100 wt. parts of the component (a1), preferably 1 to 10 wt. parts, and produced by mixing and/or kneading/granulating these components.
Component (a4):
The component (a4) for the fourth invention is the same as the component (c4) for the component (C) for the propylene-based resin composition [III].
This component is incorporated to further improve resistance to scratching and impact strength of the propylene-based resin composition of the present invention.
The propylene-based resin composition [V] of the present invention comprises the component (B) for the propylene-based resin composition [I], [III] or [IV] which is further incorporated with the following component (b3) at 30 wt. parts or less per 100 wt. parts of the totaled components (b1) and (b2), preferably 1 to 20 wt. parts, and produced by mixing and/or kneading/granulating these components.
Component (b3):
The component (b3) for the fifth invention is the same as the component (a3) for the component (A) for the propylene-based resin composition [I].
This component is incorporated to further improve impact strength of the propylene-based resin composition of the present invention.
The propylene-based resin composition [VI] of the present invention comprises the component (B) for the propylene-based resin composition [I], [III], [IV] or [V] which is further incorporated with the following component (b4) at 30 wt. parts or less per 100 wt. parts of the totaled components (b1) and (b2), preferably 0.1 to 9 wt. parts, and produced by mixing and/or kneading/granulating these components.
Component (b4):
The component (b4) for the sixth invention is the same as the component (c4) for the component (C) for the propylene-based resin composition [III], or component (a4) for the component (A) for the propylene-based resin composition [IV].
This component is incorporated to further improve resistance to scratching and impact strength of the propylene-based resin composition of the present invention.
The propylene-based resin composition [VII] of the present invention comprises the component (B) for the propylene-based resin composition [I], [III], [IV], [V] or [VI] which is further incorporated with a fatty acid amide or its derivative at 0.1 to 9 wt. parts per 100 wt. parts of the totaled components (b1) and (b2), and produced by mixing and/or kneading/granulating these components.
The fatty acid amide or its derivative is selected from the compounds for the component (c5) for the component (C) for the propylene-based resin composition [III].
This component is incorporated to further improve resistance to scratching and impact strength of the propylene-based resin composition of the present invention.
The propylene-based resin composition [VIII] of the present invention comprises the component (B) for the propylene-based resin composition [I], [III], [IV], [V], [VI] or [VII] which is further incorporated with a higher fatty acid or its metallic salt at 0.1 to 5 wt. parts per 100 wt. parts of the totaled components (b1) and (b2), and produced by mixing and/or kneading/granulating these components:
The higher fatty acids or its metallic salts include stearic acid, 12-hydroxystearic acid, and metallic salts, e.g., calcium stearate and magnesium stearate.
This component is incorporated to improve dispersion of talc and/or wollastonite in the propylene-based resin composition of the present invention.
The method of molding the propylene-based resin composition of the present invention is not limited, and a known method may be used for mixing the components (A) and (B); (A), (B) and (C); or these components further incorporated, as required, with the additional (optional) component. These components in a specific ratio are mixed by a known machine, e.g., Henschel mixer, tumbler and ribbon blender.
The mixing process may be followed by melting/kneading and granulation to mold the components into pellets. The kneading and granulation can be effected by the conventional kneader, e.g., extruder (e.g., of monoaxial or biaxial type), Banbury mixer, roll, Brabender Plastograph, or another mixer, set at around 180 to 240xc2x0 C. Of these, an extruder, in particular biaxial extruder, is more preferable. In the above process, the components may be mixed and kneaded altogether or separately, e.g., part of the component (A) is kneaded with the component (B) and optional component, when used, and the remainder is then mixed/kneaded with the mixture, to be granulated.
The components (A) and (B); (A), (B) and (C); or these components further incorporated, as required, with the optional component may be directly fed into a hopper or the like of an injection molder to be molded.
The preferable methods include mixing and melting/kneading the components (A) and (B) or (A), (B) and (C) kneaded and granulated beforehand into pellets; or the pelletized components (A) and (B) or (A), (B) and (C) are mixed and then directly fed into an injection molder. The particularly preferable method is mixing the components (A) and (B) or (A), (B) and (C) and directly feeding the into an injection molder.
The present invention gives the product of any inorganic filler content by changing the component (A)/component (B) mixing ratio.
The propylene-based composition of the present invention may be molded into various types of articles by a method selected from various known methods, including injection molding (including gas injection molding), press injection molding, extrusion, blow molding, calendering, inflation molding, and film-molding monoaxial and biaxial stretching. Of these, injection molding and press injection molding are more preferable.